Toml/doc Operation and Maintenance update

[gustawlippa]

This PR updates the Operation and Maintenance part of the documentation to reflect the TOML configuration. It also contains many general fixes, like typos, grammar, etc (sometimes in files located outside the O&A part of the docs).
I did not touch the Reloading-configuration-on-a-running-system.md file as I'm not sure what to do with it. It seems to not really be reflected in the new TOML config (e.g. no node_specific_options in the TOML config). I hesitated from adding something like "This functionality is only available if you are using the older, cfg config format" but this may be the best way to deal with this issue for now. I'd be happy to hear reviewers opinions on this topic.

[mongoose-im]

8620.1 / Erlang 23.0.3 / small_tests / da7d2ad
Reports root / small

---

8620.2 / Erlang 23.0.3 / internal_mnesia / da7d2ad
Reports root/ big
OK: 1487 / Failed: 0 / User-skipped: 165 / Auto-skipped: 0

---

8620.3 / Erlang 23.0.3 / odbc_mssql_mnesia / da7d2ad
Reports root/ big
OK: 2760 / Failed: 0 / User-skipped: 228 / Auto-skipped: 0

---

8620.4 / Erlang 23.0.3 / mysql_redis / da7d2ad
Reports root/ big
OK: 2755 / Failed: 0 / User-skipped: 233 / Auto-skipped: 0

---

8620.7 / Erlang 23.0.3 / elasticsearch_and_cassandra_mnesia / da7d2ad
Reports root/ big
OK: 330 / Failed: 0 / User-skipped: 38 / Auto-skipped: 0

---

8620.6 / Erlang 23.0.3 / ldap_mnesia / da7d2ad
Reports root/ big
OK: 1399 / Failed: 0 / User-skipped: 253 / Auto-skipped: 0

---

8620.5 / Erlang 23.0.3 / riak_mnesia / da7d2ad
Reports root/ big
OK: 1621 / Failed: 0 / User-skipped: 177 / Auto-skipped: 0

---

8620.9 / Erlang 22.3 / pgsql_mnesia / da7d2ad
Reports root/ big / small
OK: 2773 / Failed: 0 / User-skipped: 215 / Auto-skipped: 0

[codecov]

Codecov Report

Merging #2899 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2899      +/-   ##
==========================================
+ Coverage   79.14%   79.16%   +0.01%     
==========================================
  Files         379      379              
  Lines       32752    32752              
==========================================
+ Hits        25923    25927       +4     
+ Misses       6829     6825       -4     

Impacted Files	Coverage Δ
src/ejabberd_config.erl	76.99% <ø> (ø)
src/ejabberd_admin.erl	60.00% <100.00%> (ø)
src/pubsub/node_hometree.erl	77.77% <0.00%> (-5.56%)	⬇️
src/event_pusher/mod_event_pusher.erl	83.33% <0.00%> (-2.78%)	⬇️
src/cassandra/mongoose_cassandra_worker.erl	71.69% <0.00%> (-0.95%)	⬇️
src/pubsub/mod_pubsub_db_mnesia.erl	92.40% <0.00%> (-0.43%)	⬇️
src/mod_muc_log.erl	77.29% <0.00%> (ø)
src/mod_muc_room.erl	77.60% <0.00%> (+0.05%)	⬆️
src/pubsub/mod_pubsub.erl	71.93% <0.00%> (+0.05%)	⬆️
src/ejabberd_c2s.erl	89.26% <0.00%> (+0.22%)	⬆️
... and 3 more

---

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[NelsonVides]

Just one comment, otherwise fantastic, thanks for the work! 👍

[chrzaszcz]

A lot of really good changes here. I just have a few minor questions.

[chrzaszcz]

Just an alternative, see which looks better:

  config_schema = [
    {field = "roomname", value = "The room"},
    {field = "subject", value = "Chit-chat"},
    {field = "background", value = ""},
    {field = "notification_sound", value = ""}
  ]

Btw, how do we eliminate default_config? it seems to be a config option created internally by muc_light, I wonder why it was in the example then.

[gustawlippa]

Thanks for the suggestion, it looks better I think, but I've made a big mistake. From what I'm reading now, the whole section doesn't make any sense as described now - without the default_config option (as is in MIM from 3.6) the problem described in this paragraph will not appear. So it's completely senseless to describe it with TOML config as this problem only appears in older MIMs. I will revert changes to this file because of that.

[gustawlippa]

I think it's correct now that it's reverted.

[chrzaszcz]

I think it's all good now.